1、BRITISH STANDARDBS ISO 15105-1:2007Plastics Film and sheeting Determination of gas-transmission rate Part 1: Differential-pressure methodsICS 83.140.10g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40
2、g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS ISO 15105-1:2007This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2007 BSI 2007ISBN 978 0 580 55150 5National forewordThis British Standard is the UK implementation of ISO 15105-
3、1:2007. It supersedes BS ISO 15105-1:2002 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee PRI/75, Plastics and rubber film and sheets.A list of organizations represented on this committee can be obtained on request to its secretary.This publication doe
4、s not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.Amendments issued since publicationAmd. No. Date CommentsReference numberISO 15105-1:2007(E)INTERNAT
5、IONAL STANDARD ISO15105-1Second edition2007-10-15Plastics Film and sheeting Determination of gas-transmission rate Part 1: Differential-pressure methods Plastiques Film et feuille Dtermination du coefficient de transmission dun gaz Partie 1: Mthodes en pression diffrentielle BS ISO 15105-1:2007ii ii
6、iContents Page Foreword iv 1 Scope . 1 2 Normative references . 1 3 Terms and definitions. 1 4 Principle. 2 5 Test specimens . 2 6 Apparatus, procedure and calculation . 2 7 Expression of results . 2 8 Precision 2 9 Test report . 2 Annex A (normative) Method using a pressure sensor . 4 A.1 Applicabi
7、lity. 4 A.2 Apparatus and materials 4 A.3 Conditioning and test temperature. 5 A.4 Procedure 6 A.5 Calculation. 7 Annex B (normative) Method using a gas chromatograph 8 B.1 Applicability. 8 B.2 Apparatus and materials 8 B.3 Calibration graph 10 B.4 Conditioning and test temperature. 10 B.5 Procedure
8、 10 B.6 Calculation. 11 Bibliography . 12 BS ISO 15105-1:2007iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical co
9、mmittees. Each member body interested in a subject for which a technical committee has been established has the right to be represented on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with th
10、e International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft Internati
11、onal Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this document may be
12、the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 15105-1 was prepared by Technical Committee ISO/TC 61, Plastics, Subcommittee SC 11, Products. This second edition cancels and replaces the first edition (ISO 15105-1:2002), which has b
13、een revised to include a second method which uses a gas chromatograph to measure the amount of gas which permeates through the test specimen. ISO 15105 consists of the following parts, under the general title Plastics Film and sheeting Determination of gas-transmission rate: Part 1: Differential-pre
14、ssure methods Part 2: Equal-pressure method BS ISO 15105-1:20071Plastics Film and sheeting Determination of gas-transmission rate Part 1: Differential-pressure methods 1 Scope This part of ISO 15105 specifies two methods for determining the gas transmission rate of single-layer plastic film or sheet
15、 and multi-layer structures under a differential pressure. One method uses a pressure sensor, the other a gas chromatograph, to measure the amount of gas which permeates through a test specimen. 2 Normative references The following referenced documents are indispensable for the application of this d
16、ocument. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 4593, Plastics Film and sheeting Determination of thickness by mechanical scanning 3 Terms and definitions For the purposes of
17、this part of ISO 15105, the following terms and definitions apply. 3.1 gas transmission rate GTR volume of gas passing through a plastic material, per unit area and unit time, under unit partial-pressure difference between the two sides of the material NOTE When the gas used is oxygen, the value obt
18、ained is the oxygen transmission rate (O2GTR). 3.2 gas permeability coefficient of gas permeability P volume of gas passing through a plastic material of unit thickness, per unit area and unit time, under unit partial-pressure difference between the two sides of the material NOTE 1 The theoretical v
19、alue of P is given by P = GTR d see Equations (A.2) and (B.2). NOTE 2 Although P is a physical property of a polymeric material, differences in film preparation affecting polymer orientation and crystal structure will have an effect on the permeation properties. BS ISO 15105-1:20072 4 Principle A te
20、st specimen is mounted in a gas transmission cell (see Figures A.1 and B.1) so as to form a sealed barrier between two chambers. The lower-pressure chamber is evacuated, followed by evacuation of the higher-pressure chamber. A gas is introduced into the evacuated higher-pressure chamber and permeate
21、s into the lower-pressure chamber. The amount of gas which permeates through the specimen is determined by the increase in pressure on the lower-pressure side or by gas chromatography. 5 Test specimens 5.1 Test specimens shall be representative of the material under investigation, free from shrivell
22、ing, folds and pinholes, and of uniform thickness. They shall be larger than the gas transmission area of the measurement cell and be capable of being mounted airtight. 5.2 Use three specimens unless otherwise specified or agreed upon among the interested parties. 5.3 Mark the side of the material f
23、acing the permeating gas. NOTE In principle, the test should replicate the actual conditions of use, with the gas passing from the inside to the outside of e.g. packaging material, or vice versa. 5.4 Measure the thickness of each specimen in accordance with ISO 4593, to the nearest 1 m, at at least
24、five points distributed over the entire test area, and record the minimum, maximum and average values. 6 Apparatus, procedure and calculation Of the several methods available for measuring the amount of gas permeating through a specimen, two are described in the annexes: Annex A: pressure sensor met
25、hod; Annex B: gas chromatography method. 7 Expression of results Express the test result as the arithmetic mean of the results obtained for all the specimens, rounding to three significant figures. 8 Precision The precision of these test methods is not known because interlaboratory data are not avai
26、lable. When interlaboratory data are obtained, a precision statement will be added at the following revision. 9 Test report The test report shall include the following information: a) a reference to this part of ISO 15105; b) the method of measurement used (pressure sensor or gas chromatography); c)
27、 all details necessary for identification of the test apparatus used (make, manufacturer, etc.), including, when a pressure sensor is used, the type of pressure sensor; BS ISO 15105-1:20073d) all details necessary for identification of the sample tested; e) the method of preparation of the test spec
28、imens; f) the side of the specimen which faced the permeating gas; g) the pressure, composition and purity of the gas used; h) the average, minimum and maximum thickness of each specimen; i) the number of specimens tested; j) details of test specimen conditioning; k) the temperature and humidity of
29、the laboratory; l) the test results; m) the date of the test. BS ISO 15105-1:20074 Annex A (normative) Method using a pressure sensor A.1 Applicability This method can be used to determine the gas transmission rate of any plastic material. A.2 Apparatus and materials A.2.1 General Figure A.1 shows a
30、n example of an apparatus for determining gas transmission rate using a pressure sensor. The apparatus consists of a gas transmission cell designed to allow a gas to permeate through a specimen, a pressure sensor to detect the pressure change due to the permeation of the gas through the specimen, a
31、gas feeder to supply the gas to the transmission cell, a cell volume-control device and a vacuum pump. A.2.2 Transmission cell The transmission cell shall consist of an upper (high-pressure) chamber and a lower (low-pressure) chamber, designed so that the gas transmission area is constant for any sp
32、ecimen mounted in the cell. The high-pressure chamber shall have an inlet for the gas and the low-pressure chamber shall be connected to a pressure sensor. The surfaces in contact with the specimen shall be smooth and flat so that leakage does not occur. The diameter of the gas transmission area sha
33、ll be 10 mm to 150 mm. A.2.3 Pressure sensor The sensor shall be capable of determining the change in pressure on the low-pressure side with a minimum sensitivity of 5 Pa (0,038 mmHg). A vacuum gauge with no mercury, an electronic diaphragm-type sensor or another suitable type shall be used. A.2.4 G
34、as feeder The gas feeder is basically a reservoir designed to store the gas. The gas is fed to the high-pressure side of the cell from the feeder. In order to determine the pressure in the reservoir, a manometer with a minimum sensitivity of 100 Pa (0,75 mmHg) is fitted. The reservoir shall have suf
35、ficient capacity such that permeation of the gas through the specimen does not cause any drop in pressure on the high-pressure side. A.2.5 Cell volume-control device In order to extend the transmission rate measurement range, the volume of the low-pressure chamber may be adjusted by a cell volume-co
36、ntrol device such as an additional reservoir or an adapter. A.2.6 Gas The gas used should preferably have a purity greater than 99,5 %. The use of gases of other purities shall be subject to agreement between the interested parties. BS ISO 15105-1:20075Key 1 transmission cell 7 vacuum pump 2 specime
37、n 8 gas supply 3 filter paper 9 valve 1 4 cell volume-control device 10 valve 2 5 pressure sensor 11 valve 3 6 gas feeder 12 valve 4 Figure A.1 Example of gas transmission rate measurement apparatus using a pressure sensor A.2.7 Vacuum pump A vacuum pump capable of producing a vacuum better than 10
38、Pa (0,075 mmHg) in the low-pressure chamber shall be used. A.3 Conditioning and test temperature A.3.1 Conditioning Dry the specimens for not less than 48 h at the same temperature as that at which the test is to be carried out, using calcium chloride or another suitable drying agent in a desiccator
39、. Drying will not normally be required for non-hygroscopic materials. BS ISO 15105-1:20076 A.3.2 Test temperature Carry out the test in a room kept at 23 C 2 C, unless otherwise specified. Other test conditions, for example those specified in ISO 291, can be chosen subject to agreement between the i
40、nterested parties. A.4 Procedure A.4.1 Spread a filter paper (3 in Figure A.1) having the same size as the gas transmission area over the bottom of the low-pressure chamber. NOTE The filter paper is used to support the specimen film. A filter paper of the type generally used for chemical analysis, o
41、f thickness about 0,2 mm to 0,3 mm, is recommended for this purpose. A.4.2 Coat the flat edges of the two halves of the transmission cell thinly and uniformly with vacuum grease, and mount the specimen over the lower chamber so that no creasing or slackness occurs. A.4.3 Place a rubber sealing ring
42、on the specimen, followed by the upper part of the cell. Clamp the two halves of the cell together with uniform pressure so that the specimen is completely sealed in place. A.4.4 Close valve 1 (9 in Figure A.1) and valve 2 (10), and open valve 3 (11). Start the vacuum pump and then open valve 2 (10)
43、. Air will be evacuated first from the low-pressure chamber, followed by the high-pressure chamber. Continue until evacuation is complete. Care is necessary here because the time taken to completely exhaust the cell will depend on the permeability of the specimen. NOTE The low-pressure chamber is ev
44、acuated first to ensure that the specimen fits close to the filter paper. A.4.5 When all the air has been evacuated, stop the vacuum pump, shutting valve 2 (10) and valve 3 (11) to maintain the vacuum. A.4.6 If the pressure on the low-pressure side rises, repeat A.4.3 to A.4.5 to ensure that no air
45、is leaking into the cell and to complete any degassing. A.4.7 Introduce the gas into the high-pressure chamber by opening valve 1 (9), shutting off the gas supply when a pressure of about one atmosphere has been reached. Record the pressure phin the high-pressure chamber as indicated by the manomete
46、r associated with the gas feeder. An increase in pressure in the low-pressure chamber will confirm transmission of the gas. A.4.8 Plot a curve of the pressure in the low-pressure chamber versus time, continuing until equilibrium has been reached as indicated by a straight line. A.4.9 Determine the s
47、lope of the straight-line portion of the transmission curve (dp/dt, see Clause A.5). An automatically recorded transmission curve may also be used. BS ISO 15105-1:20077A.5 Calculation Calculate the gas transmission rate and the gas permeability, or coefficient of gas permeability, from Equations (A.
48、1) and (A.2). a) Gas transmission rate chdGTRdV pR Tp A t= (A.1) where GTR is the gas transmission rate, expressed in moles per square metre second pascal mol/(m2sPa); Vcis the volume of the low-pressure chamber, expressed in litres; T is the test temperature, expressed in kelvins; phis the pressure
49、 of the gas in the high-pressure chamber, expressed in pascals; A is the transmission area of the specimen, expressed in square metres; dp/dt is the change in pressure per unit time in the low-pressure chamber, expressed in pascals per second; R is the gas constant (= 8,31 103), expressed in litre pascals per kelvin mole (lPa)/(Kmol). b) Gas permeability, or coefficient of gas permeability P = GTR d (A.2) where P is the gas permeability, or coefficient of gas permeability, expressed in mole metres per square metre second pas
